A late night flex is when you decide going to a place in the daytime isn't vibey enough, so you go to that same place but at 2am. Crazy people are usually the only people who partake in such activities.
Turban: Sayin issa late night flex?
Bestie: Where tho
Turban: McDonalds, let's get nuggets with the spicy buffalo sauce
Bestie: Say no more